Conveyance system, conveying method, and program

ABSTRACT

A conveyance system includes a conveyance robot that conveys a carried item adjacent to an obstacle, by approaching the carried item in a predetermined control target direction, getting into under the carried item, and moving when the carried item is lifted by an elevating device. The conveyance system obtains information on a control error indicating deflection in a yawing direction of a moving direction of the conveyance robot relative to the control target direction, when the conveyance robot gets into under the carried item, determines whether the carried item interferes with the obstacle, when the conveyance robot starts moving in the condition where the carried item is lifted, based on the obtained control error information, and corrects the control target direction used when the conveyance robot gets into under the carried item, to reduce the control error, when determining that the carried item interferes with the obstacle.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2021-026156 filed on Feb. 22, 2021, incorporated herein by reference inits entirety.

BACKGROUND 1. Technical Field

The disclosure relates to a conveyance system that conveys a carrieditem, a conveying method, and a program.

2. Description of Related Art

A conveyance system is known which includes a conveyance robot thatconveys a carried item, by getting into under the carried item, andmoving in a condition where the carried item is lifted by an elevatingdevice (see, for example, Japanese Patent No. 6247796).

SUMMARY

When the conveyance robot gets into under the carried item, there mayarise a control error by which the moving direction of the conveyancerobot deflects in the yawing direction relative to a predeterminedcontrol target direction. Due to the control error, the carried item mayinterfere with an obstacle when the conveyance robot starts moving inthe condition where the carried item is lifted by the elevating device.

The disclosure provides a conveyance system that can curb interferencebetween a carried item and an obstacle due to a control error of aconveyance robot, and also provides a conveying method, and a program.

A first aspect of the disclosure is concerned with a conveyance systemincluding a conveyance robot configured to convey a carried itemadjacent to an obstacle, by approaching the carried item in apredetermined control target direction relative to the carried item,getting into under the carried item, and moving in a condition in whichthe carried item is lifted by an elevating device. The conveyance systemincludes an error obtaining unit that obtains information on a controlerror indicating deflection in a yawing direction of a direction ofmovement of the conveyance robot relative to the predetermined controltarget direction, when the conveyance robot gets into under the carrieditem, a determining unit that determines whether the carried iteminterferes with the obstacle, when the conveyance robot starts moving inthe condition in which the carried item is lifted by the elevatingdevice, based on the information on the control error obtained by theerror obtaining unit, and a correcting unit that corrects thepredetermined control target direction used when the conveyance robotgets into under the carried item, to reduce the control error, when thedetermining unit determines that the carried item interferes with theobstacle. In the first aspect, the correcting unit may correct thepredetermined control target direction, to reduce the control error,when the predetermined control target direction used when the conveyancerobot gets into under the carried item is in parallel with the obstacle.In the first aspect, the determining unit may determine that the carrieditem interferes with the obstacle, when the determining unit determinesthat the carried item and the obstacle get closer to each other when theconveyance robot starts moving in the condition in which the carrieditem is lifted by the elevating device. In the first aspect, thedetermining unit may determine that the carried item interferes with theobstacle, when the determining unit determines that the carried item andthe obstacle get closer to each other when the conveyance robot startsmoving in the condition in which the carried item is lifted by theelevating device, and a clearance between the carried item and theobstacle is equal to or smaller than a predetermined value. A secondaspect of the disclosure is concerned with a method of conveying acarried item adjacent to an obstacle, by causing a conveyance robot toapproach the carried item in a predetermined control target directionrelative to the carried item, get into under the carried item, and movein a condition in which the carried item is lifted by an elevatingdevice. The method includes a step of obtaining information on a controlerror indicating deflection in a yawing direction of a direction ofmovement of the conveyance robot relative to the predetermined controltarget direction, when the conveyance robot gets into under the carrieditem, a step of determining whether the carried item interferes with theobstacle, when the conveyance robot starts moving in the condition inwhich the carried item is lifted by the elevating device, based on theobtained information on the control error, and a step of correcting thepredetermined control target direction used when the conveyance robotgets into under the carried item, to reduce the control error, when itis determined that the carried item interferes with the obstacle. Athird aspect of the disclosure is concerned with a program for conveyinga carried item adjacent to an obstacle, by causing a conveyance robot toapproach the carried item in a predetermined control target directionrelative to the carried item, get into under the carried item, and movein a condition in which the carried item is lifted by an elevatingdevice. The program causes a computer to execute the steps of: obtaininginformation on a control error indicating deflection in a yawingdirection of a direction of movement of the conveyance robot relative tothe predetermined control target direction, when the conveyance robotgets into under the carried item, determining whether the carried iteminterferes with the obstacle, when the conveyance robot starts moving inthe condition in which the carried item is lifted by the elevatingdevice, based on the obtained information on the control error, andcorrecting the predetermined control target direction used when theconveyance robot gets into under the carried item, to reduce the controlerror, when it is determined that the carried item interferes with theobstacle.

According to the disclosure, the conveyance system that can curbinterference between the carried item and the obstacle due to thecontrol error of the conveyance robot, the conveying method, and theprogram can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance ofexemplary embodiments of the disclosure will be described below withreference to the accompanying drawings, in which like signs denote likeelements, and wherein:

FIG. 1 is a schematic view of a conveyance system according to oneembodiment;

FIG. 2 is a block diagram of the conveyance system according to theembodiment;

FIG. 3 is a view showing conditions in which a robot main body gets intounder a carried item in a control target direction;

FIG. 4 is a view showing a control error that arises when a conveyancerobot gets into under the carried item;

FIG. 5 is a block diagram schematically showing the system configurationof a computing unit according to the embodiment;

FIG. 6 is a view showing a condition in which the direction of movementof the conveyance robot deflects by a control error in the positivedirection;

FIG. 7 is a view showing the case where there is a clearance between acarried item and an obstacle;

FIG. 8 is a view showing a condition in which the control targetdirection is corrected in the positive direction;

FIG. 9 is a flowchart illustrating the flow of a conveying methodaccording to the embodiment; and

FIG. 10 is a view showing the configuration of a conveyance system thatdoes not include a host management device.

DETAILED DESCRIPTION OF EMBODIMENTS

While this disclosure will be described through one embodiment of thedisclosure, the disclosure defined in any of the appended claims is notlimited to the embodiment as described below. For explicit explanation,the following description and the drawings are subjected to omission orsimplification as appropriate. In each drawing, the same reference signsare assigned to the same elements, and repeated description of theelements is omitted as needed.

FIG. 1 is a schematic view of a conveyance system according to theembodiment. Referring to FIG. 1, the conveyance system 1 according tothe embodiment will be described. In the conveyance system 1, aconveyance robot 200 that autonomously moves in a predetermined regionconveys a carried item that is to be conveyed.

The conveyance system 1 shown in FIG. 1 is one example of the conveyancesystem. For example, the conveyance system 1 can convey a carrier shelfon which dishes, drugs, medical appliances, etc. are placed, to a presetlocation, in a facility, such as a hospital. The conveyance system 1has, as main constituent elements, a host management device 100,conveyance robot 200, and environment camera 500.

The host management device 100 grasps conditions in the facility, usingthe environment camera 500, etc., and controls the conveyance robot 200,to convey the carried item. The host management device 100 may beprovided in the facility in which the conveyance robot 200 is inoperation, or may be installed in a location away from the facility. Thehost management device 100 has a communication function, and is able tocommunicate with equipment, such as the conveyance robot 200 and theenvironment camera 500, in the facility.

The conveyance robot 200 is configured as an autonomous mobile robotthat moves on a floor of a hospital, for example. The conveyance robot200 can convey a carried item, such as a carrier shelf, from a givenlocation (a point of departure) to another location (destination).

The configuration of the conveyance robot 200 will be described indetail. The conveyance robot 200 shown in FIG. 1 is one example of anautonomous mobile robot, and may take another form.

The conveyance robot 200 according to this embodiment has a robot mainbody 210 in the shape of a generally rectangular parallelepiped, adistance sensor 220 attached to the front face of the robot main body210, an elevating unit 230 provided on the top face of the robot mainbody 210, and wheels 213 attached to the right and left side faces ofthe robot main body 210.

A wheel driving unit that drives the wheels 213 is provided in the robotmain body 210. While a pair of wheels 213 is attached to the right andleft side faces of the robot main body 210, the arrangement of thewheels 213 is not limited to this. For example, two pairs of wheels maybe attached to the right and left side faces of the robot main body 210,or a pair of wheels and one auxiliary wheel may be attached to the rightand left side faces of the robot main body 210.

The distance sensor 220 is in the form of, for example, a laser sensor,ultrasonic sensor, camera, or the like. The distance sensor 220 obtainsdistance information of an obstacle and a carried item present aroundthe conveyance robot 200. In this connection, the robot main body 210may be provided with two or more distance sensors 220, and the locationsat which the distance sensors 220 are provided may be selected asdesired.

The elevating unit 230 is one specific example of the elevating device.The elevating unit 230 generally refers to an arrangement that goes upand down relative to the robot main body 210, and consists of a plate211 on which the carried item is placed, an elevating mechanism thatraises and lowers the plate 211, etc.

The conveyance robot 200 proceeds toward the carried item in apredetermined control target direction (which will be called “controltarget direction”), and gets into under the carried item, based on thedistance information of the carried item obtained by the distance sensor220, and route plan information that will be described later. Then,after getting into under the carried item, the conveyance robot 200lifts the carried item by means of the elevating unit 230, and conveysthe carried item by moving in a condition where the item is lifted up.

Next, the system configuration of the conveyance system 1 will bedescribed in detail with reference to FIG. 2. FIG. 2 is a block diagramof the conveyance system 1 according to the embodiment. The conveyancesystem 1 has the host management device 100, conveyance robot 200, andenvironment cameras 501 to 50 n.

Initially, the host management device 100 will be described. The hostmanagement device 100 has a computing unit 110, storage unit 120, andcommunication unit 140. The storage unit 120 stores a floor map 121,robot information 122, robot control parameters 123, and route planinformation 124.

The computing unit 110 is a processor, such as a central processing unit(CPU), that can execute programs, for example, and is able to performprocessing as described later, via a load conveyance program.

The computing unit 110 gives an operation command to the conveyancerobot 200, according to a preset schedule. At this time, the computingunit 110 issues the operation command to the conveyance robot 200, viathe communication unit 140.

When issuing the operation command, the computing unit 110 grasps thepoint of departure and destination of the conveyance robot 200,referring to the floor map 121, and transmits a movement procedure tothe conveyance robot 200, referring to the route plan information 124.Also, the computing unit 110 determines operating conditions of thecomputing unit 110, referring to the robot information 122 and the robotcontrol parameters 123, and transmits the operating conditions thusdetermined, to the conveyance robot 200, via the communication unit 140.

As one of the operating conditions, the computing unit 110 sets thecontrol target direction used when the conveyance robot 200 gets intounder the carried item, for example. The computing unit 110 sends theset control target direction to the conveyance robot 200, via thecommunication unit 140.

The communication unit 140 is an interface that is communicablyconnected to the conveyance robot 200, and consists of a circuit, etc.,that modulates or demodulates signals transmitted via an antenna, forexample. The communication unit 140 is connected to the computing unit110, and supplies a given signal received from the conveyance robot 200via wireless communications, to the computing unit 110. Thecommunication unit 140 sends a given signal received from the computingunit 110, to the conveyance robot 200. The communication unit 140 isalso configured to be able to wirelessly communicate with theenvironment cameras 501 to 50 n.

Next, the conveyance robot 200 will be described. The conveyance robot200 has a control processor 240, sensors 250, a wheel driving unit 252,storage unit 260, and communication unit 270.

The control processor 240, which is an information processing unithaving a processor, such as a CPU, obtains information from respectivecomponents of the conveyance robot 200, and sends commands to therespective components. The control processor 240 controls operation ofthe wheel driving unit 252 and the elevating unit 230.

The sensors 250 generally refer to various sensors of the conveyancerobot 200. The sensors 250 include the distance sensor 220, an attitudesensor, a rotary encoder, and so forth. The sensors 250 are connected tothe control processor 240, and supply detected signals to the controlprocessor 240.

The wheel driving unit 252 includes a motor driver, etc. for drivingmotors of the wheels 213. The elevating unit 230 includes a motordriver, etc. for driving a motor of the elevating mechanism. The wheeldriving unit 252 and the elevating unit 230 are connected to the controlprocessor 240, and are driven in response to commands from the controlprocessor 240.

The storage unit 260 includes a non-volatile memory, and stores a floormap and operation parameters. The floor map is a database needed forautonomous movement of the conveyance robot 200, and includesinformation that is identical with at least a part of the floor mapstored in the storage unit 120 of the host management device 100. Thefloor map may include position information of an obstacle and a carrieditem. The operation parameters include the control target directiontransmitted from the computing unit 110 of the host management device100.

For example, the conveyance robot 200 conveys a carried item adjacent toan obstacle. The carried item adjacent to the obstacle refers to notonly the carried item that is in contact with the obstacle, but also thecarried item that is not in contact with the obstacle but is located inthe vicinity of the obstacle. One example of the carried item adjacentto the obstacle is a carried item, such as a carrier shelf, that isplaced against a wall.

The control processor 240 controls the wheel driving unit 252, based onthe distance information of the obstacle detected by the distance sensor220, and the distance information of the carried item adjacent to theobstacle, so that the conveyance robot 200 gets into under the carrieditem.

The control processor 240 may control the wheel driving unit 252, basedon the position information of the obstacle and the carried item in thefloor map 121, so that the conveyance robot 200 gets into under thecarried item. Further, the control processor 240 may control the wheeldriving unit 252, based on image information of the obstacle and thecarried item captured by the environment camera 500, so that the robotmain body 210 gets into under the carried item.

As shown in (1) of FIG. 3, the control processor 240 controls the wheeldriving unit 252, based on the route plan information 124, and thedistance information of the carried item X adjacent to the obstacle Yobtained by the distance sensor 220, so that the conveyance robot 200approaches the carried item X in the control target direction, and getsinto under the carried item X. Where the carried item X is rectangularas viewed from above, for example, the control target direction isperpendicular to one side of the rectangular item X.

When the control processor 240 determines that the conveyance robot 200is located under the carried item X adjacent to the obstacle Y, based onthe distance information of the carried item X detected by the distancesensor 220, the control processor 240 controls the elevating unit 230,to lift the carried item X. Then, as shown in (2) of FIG. 3, the controlprocessor 240 controls the wheel driving unit 252 so that the conveyancerobot 200 moves in the direction P in a condition where the carried itemX is lifted by the elevating unit 230, and conveys the carried item X tothe destination.

In the meantime, when a conveyance robot gets into under a carried item,there may arise a control error by which the direction P of movementdeflects in the yawing direction, relative to the control targetdirection. Conventionally, when the conveyance robot starts moving in acondition where the carried item is lifted by the elevating unit, thecarried item and the obstacle may interfere with each other, due to thecontrol error.

For example, as shown in FIG. 4, when the conveyance robot 200 gets intounder the carried item X, there may arise a control error α by which thedirection P of movement deflects relative to the control targetdirection in the counterclockwise direction. In the followingdescription, the direction of deflection is positive when the directionP of movement deflects relative to the control target direction in theclockwise direction, and the direction of deflection is negative whenthe direction P of movement deflects relative to the control targetdirection in the counterclockwise direction.

In this case, when the conveyance robot 200 starts moving in thedirection P of the arrow in a condition where the carried item is liftedby the elevating unit 230, the conveyance robot 200 moves in such adirection as to make the carried item X and the obstacle Y closer toeach other; as a result, the carried item X and the obstacle Y interferewith each other. In FIG. 4, the deflection angle of the control error ais expressed such that it looks larger than in reality, for the sake ofeasier understanding.

Also, when the control target direction used when the conveyance robot200 gets into under the carried item X is in parallel with the obstacleY, as shown in FIG. 4, the carried item X interferes with the obstacle Ydue to the control error α, when the conveyance robot 200 starts moving,as described above.

On the other hand, when the conveyance system 1 according to thisembodiment determines that the carried item X interferes with theobstacle Y, it corrects the control target direction used when theconveyance robot 200 gets into under the carried item X, so as to reduceor eliminate the control error α. Thus, the control target direction iscorrected to reduce or eliminate the control error α, thereby to curbthe interference between the carried item X and the obstacle Y due tothe control error α.

FIG. 5 is a block diagram schematically showing the system configurationof the computing unit according to this embodiment. The computing unit110 according to this embodiment has an error obtaining unit 111 thatobtains a control error α of the conveyance robot 200, a determiningunit 112 that determines whether a carried item X interferes with anobstacle Y, and a correcting unit 113 that corrects the control targetdirection.

The error obtaining unit 111 obtains information on the control error ain the movement direction P relative to the control target directionwhen the conveyance robot 200 gets into under the carried item X.

The control error α is a value determined by the characteristics of themechanisms of respective parts of the conveyance robot 200 and thesensors, and can be empirically obtained in advance. The information onthe control error a includes the deflection angle in the yawingdirection and the positive/negative direction relative to the controltarget direction.

The information on the control error α of the conveyance robot 200 maybe set in advance in the robot information 122 in the storage unit 120,for example. The error obtaining unit 111 obtains information on thecontrol error a relative to the control target direction, from the robotinformation 122 in the storage unit 120. The information on the controlerror α may be set as an operation parameter in the storage unit 260 ofthe conveyance robot 200. In this case, the error obtaining unit 111 mayobtain the information on the control error a from the storage unit 260of the conveyance robot 200. The error obtaining unit 111 outputs theobtained information on the control error α to the determining unit 112.

The determining unit 112 determines whether the carried item Xinterferes with the obstacle Y, when the conveyance robot 200 startsmoving in a condition where the carried item X is lifted by theelevating unit 230, based on the floor map 121 and route planinformation 124 stored in the storage unit 120, and the information onthe control error a obtained by the error obtaining unit 111.

For example, the determining unit 112 determines that the carried item Xinterferes with the obstacle Y, in the case where it determines that thedirection P of movement deflects by the control error α in the negativedirection, and the carried item X and the obstacle Y get closer to eachother, as shown in FIG. 4, when the conveyance robot 200 starts movingin the direction P in the condition where the carried item X is liftedby the elevating unit 230.

On the other hand, the determining unit 112 determines that the carrieditem X does not interfere with the obstacle Y, in the case where itdetermines that the direction P of movement deflects by the controlerror a in the positive direction, and the carried item X and theobstacle Y get away from each other, as shown in FIG. 6, when theconveyance robot 200 starts moving in the direction P in the conditionwhere the carried item X is lifted by the elevating unit 230.

In this connection, when there is a clearance “d” between the carrieditem X and the obstacle Y, as shown in FIG. 7, for example, thedetermining unit 112 may determine the interference between the carrieditem X and the obstacle Y, in view of the size of the clearance “d”between the carried item X and the obstacle Y, as well as the abovedetermination that the carried item X and the obstacle Y get closer toeach other when the conveyance robot 200 starts moving, as describedabove.

This is because, if the size of clearance “d” between the carried item Xand the obstacle Y is equal to or larger than a certain size, theconveyance robot 200 is able to move while avoiding interference betweenthe carried item X and the obstacle Y, owing to the clearance d, evenwhen the carried item X and the obstacle Y get closer to each other uponstart of movement of the conveyance robot 200.

More specifically, the determining unit 112 determines that the carrieditem X interferes with the obstacle Y, in the case where it determinesthat the carried item X and the obstacle Y get closer to each other,when the conveyance robot 200 starts moving in the condition where thecarried item X is lifted by the elevating unit 230, and it alsodetermines that the clearance “d” between the carried item X and theobstacle Y is equal to or smaller than a predetermined value. Thus, theinterference can be determined with higher accuracy, according to thesize of the clearance “d” between the carried item X and the obstacle Y.

The optimum value empirically obtained in advance may be set as thepredetermined value in the determining unit 112. Also, the determiningunit 112 can calculate the clearance “d” between the carried item X andthe obstacle Y, based on position information of the floor map stored inthe storage unit 260, or the distance information of the carried item Xand the obstacle Y obtained by the distance sensor 220.

When the determining unit 112 determines that the carried item Xinterferes with the obstacle Y, as described above, it outputs aninterference signal indicating the determination, to the correcting unit113.

When the determining unit 112 determines that the carried item Xinterferes with the obstacle Y, the correcting unit 113 corrects thecontrol target direction used when the conveyance robot 200 gets intounder the carried item X, so as to reduce or eliminate the control errorα. Thus, the interference between the carried item X and the obstacle Ydue to the control error α can be curbed, by correcting the controltarget direction so as to reduce or eliminate the control error α.

For example, when the determining unit 112 determines, based on theinformation on the control error α obtained by the error obtaining unit111, that the direction P of movement of the conveyance robot 200deflects by the control error α in the negative direction, as shown inFIG. 4, the correcting unit 113 corrects the control target direction tothe positive direction, so as to reduce or eliminate the control errorα.

For example, the amount of correction of the control target direction isset to an amount that completely cancels the deflection of the controlerror α. However, the correction amount is not limited to this amount,but may be larger or smaller than it. Also, the optimum valueempirically obtained may be set in advance in the correcting unit 113,as the correction amount of the control target direction.

The correcting unit 113 of the computing unit 110 sends the controltarget direction corrected as described above (which will be called“corrected control target direction”), to the conveyance robot 200, viathe communication unit 140. The conveyance robot 200 proceeds in thecorrected control target direction transmitted from the correcting unit113, relative to the carried item X, and gets into under the carrieditem X.

Conventionally, there may arise a control error α by which the directionP of movement deflects in the negative direction relative to the controltarget direction when the conveyance robot 200 gets into under thecarried item X, as shown in FIG. 4 by way of example. In this situation,according to this embodiment, the correcting unit 113 corrects thecontrol target direction to the positive direction, so as to reduce oreliminate the control error α. In this case, the conveyance robot 200gets into under the carried item X in the corrected control targetdirection, as shown in FIG. 8 by way of example. Accordingly, aftergetting into under the carried item X, the conveyance robot 200 causesthe elevating unit 230 to lift the carried item X, and moves in thedirection P in a condition where the carried item X is lifted up. Atthis time, the carried item X and the obstacle Y are spaced apart fromeach other, and do not interfere with each other.

Subsequently, a conveying method according to this embodiment will bedescribed. FIG. 9 is a flowchart illustrating the flow of the conveyingmethod according to the embodiment.

The error obtaining unit 111 of the computing unit 110 obtainsinformation on the control error α in the direction P of movementrelative to the control target direction when the conveyance robot 200gets into under the carried item X, and outputs the obtained informationon the control error α, to the determining unit 112 (step S101).

The determining unit 112 determines whether the carried item Xinterferes with the obstacle Y, when the conveyance robot 200 startsmoving in a condition where the carried item X is lifted by theelevating unit 230, based on the information on the control error αreceived from the error obtaining unit 111 (step S102).

When the determining unit 112 determines that the carried item Xinterferes with the obstacle Y (YES in step S102), the correcting unit113 corrects the control target direction used when the conveyance robot200 gets into under the carried item X, to the corrected control targetdirection for reducing or eliminating the control error α (step S103).On the other hand, when the determining unit 112 determines that thecarried item X does not interfere with the obstacle Y (NO in step S102),the correcting unit 113 finishes this routine.

The correcting unit 113 of the computing unit 110 sends the correctedcontrol target direction to the conveyance robot 200 via thecommunication unit 140 (step S104). The conveyance robot 200 proceeds inthe corrected control target direction transmitted from the correctingunit 113, and gets into under the carried item X (step S105).

After getting into under the carried item X, the conveyance robot 200causes the elevating unit 230 to lift the carried item X, and conveysthe carried item X by moving it in a lifted condition (step S106).

Thus, the conveyance system 1 according to this embodiment includes theerror obtaining unit 111 that obtains information on a control errorindicating deflection in the yawing direction of the direction ofmovement relative to the control target direction when the conveyancerobot 200 gets into under a carried item, the determining unit 112 thatdetermines whether the carried item interferes with an obstacle when theconveyance robot 200 starts moving in a condition where the carried itemis lifted by the elevating unit 230, based on the information on thecontrol error obtained by the error obtaining unit 111, and thecorrecting unit 113 that corrects the control target direction used whenthe conveyance robot 200 gets into under the carried item, so as toreduce or eliminate the control error, when the determining unit 112determines that the carried item interferes with the obstacle.

According to this embodiment, the control target direction is correctedto reduce or eliminate the control error, so that the interferencebetween the carried item and the obstacle due to the control error canbe curbed or prevented.

In the conveyance system 1 according to this embodiment, the functionsprovided in the host management device 100 and the conveyance robot 200may be installed on either of the devices depending on the use. Thefunctions of the computing unit 110, storage unit 120, etc. of the hostmanagement device 100 may be installed on the conveyance robot 200 side.

For example, a conveyance system 10 may not include the host managementdevice 100, as shown in FIG. 10. A conveyance robot 300 further includesthe computing unit 110, in addition to the configuration of the aboveembodiment. Further, the conveyance system 10 may consist solely of theconveyance robot 300, without including the environment camera(s) 500.

While some embodiments of the disclosure have been described, theseembodiments are merely exemplary, and are not intended to limit thescope of the disclosure. The novel embodiments can be carried out invarious other forms, and may be subjected to various omissions,replacements, and changes, without departing from the principle of thedisclosure. The embodiments and their modifications are included in thescope or principle of the disclosure, and included in the disclosuredescribed in the appended claims, and equivalents thereof.

According to the disclosure, it is possible to carry out the routineshown in FIG. 9, by causing a processor to execute a computer program,for example.

The program can be stored by use of a non-transitory computer readablemedium of various types, and supplied to a computer. The non-transitorycomputer readable medium may be selected from various types of tangiblestorage media. Examples of the non-transitory computer readable mediuminclude a magnetic recording medium (e.g., a flexible disk, magnetictape, hard disk drive), magneto-optical recording medium (e.g., amagneto-optical disk), CD-ROM (read-only memory), CD-R, CD-R/W, andsemiconductor memory (e.g., a mask ROM, PROM (Programmable ROM), EPROM(Erasable PROM), flash ROM, RAM (random access memory)).

The program may be supplied to a computer via a transitory computerreadable medium of various types. Examples of the transitory computerreadable medium include an electric signal, optical signal, andelectromagnetic wave. The transitory computer readable medium may supplythe program to the computer, via a wire communication path, such as anelectric wire, and an optical fiber, or a wireless communication path.

Each part of the computing unit 110 of the conveyance system 1 accordingto the above embodiment is not only realized by a program, but may alsobe partially or entirely realized by a dedicated hardware, such as anASIC (Application Specific Integrated Circuit), or FPGA(Field-Programmable Gate Array).

What is claimed is:
 1. A conveyance system including a conveyance robotconfigured to convey a carried item adjacent to an obstacle, byapproaching the carried item in a predetermined control target directionrelative to the carried item, getting into under the carried item, andmoving in a condition in which the carried item is lifted by anelevating device, comprising: an error obtaining unit that obtainsinformation on a control error indicating deflection in a yawingdirection of a direction of movement of the conveyance robot relative tothe predetermined control target direction, when the conveyance robotgets into under the carried item; a determining unit that determineswhether the carried item interferes with the obstacle, when theconveyance robot starts moving in the condition in which the carrieditem is lifted by the elevating device, based on the information on thecontrol error obtained by the error obtaining unit; and a correctingunit that corrects the predetermined control target direction used whenthe conveyance robot gets into under the carried item, to reduce thecontrol error, when the determining unit determines that the carrieditem interferes with the obstacle.
 2. The conveyance system according toclaim 1, wherein the correcting unit corrects the predetermined controltarget direction, to reduce the control error, when the predeterminedcontrol target direction used when the conveyance robot gets into underthe carried item is in parallel with the obstacle.
 3. The conveyancesystem according to claim 1, wherein the determining unit determinesthat the carried item interferes with the obstacle, when the determiningunit determines that the carried item and the obstacle get closer toeach other when the conveyance robot starts moving in the condition inwhich the carried item is lifted by the elevating device.
 4. Theconveyance system according to claim 1, wherein the determining unitdetermines that the carried item interferes with the obstacle, when thedetermining unit determines that the carried item and the obstacle getcloser to each other when the conveyance robot starts moving in thecondition in which the carried item is lifted by the elevating device,and a clearance between the carried item and the obstacle is equal to orsmaller than a predetermined value.
 5. A method of conveying a carrieditem adjacent to an obstacle, by causing a conveyance robot to approachthe carried item in a predetermined control target direction relative tothe carried item, get into under the carried item, and move in acondition in which the carried item is lifted by an elevating device,comprising: obtaining information on a control error indicatingdeflection in a yawing direction of a direction of movement of theconveyance robot relative to the predetermined control target direction,when the conveyance robot gets into under the carried item; determiningwhether the carried item interferes with the obstacle, when theconveyance robot starts moving in the condition in which the carrieditem is lifted by the elevating device, based on the obtainedinformation on the control error; and correcting the predeterminedcontrol target direction used when the conveyance robot gets into underthe carried item, to reduce the control error, when it is determinedthat the carried item interferes with the obstacle.
 6. A program forconveying a carried item adjacent to an obstacle, by causing aconveyance robot to approach the carried item in a predetermined controltarget direction relative to the carried item, get into under thecarried item, and move in a condition in which the carried item islifted by an elevating device, the program causing a computer to executethe steps of: obtaining information on a control error indicatingdeflection in a yawing direction of a direction of movement of theconveyance robot relative to the predetermined control target direction,when the conveyance robot gets into under the carried item; determiningwhether the carried item interferes with the obstacle, when theconveyance robot starts moving in the condition in which the carrieditem is lifted by the elevating device, based on the obtainedinformation on the control error; and correcting the predeterminedcontrol target direction used when the conveyance robot gets into underthe carried item, to reduce the control error, when it is determinedthat the carried item interferes with the obstacle.